Effect

Generation IV

Magma Storm traps the target, preventing it from switching and escape, and inflicts 1/16 of the target's maximum HP as damage for two to five turns upon use, in addition to the damage dealt when it is used. The quote "<Pokémon> became trapped by swirling magma!" will appear. If a trapped Pokémon uses Rapid Spin, it will be freed. If a wild Pokémon uses Magma Storm on the player's Pokémon, the player may escape if the affected Pokémon has Run Away or is holding a Smoke Ball. However, these do not allow the player to switch the Pokémon out. If the user of Magma Storm is holding a Grip Claw, the duration will always be 5 turns. Also, if an affected Pokémon is holding a Shed Shell, it can switch out.

Magma Storm has an accuracy of 70% and a base power of 120.

Generation V

Magma Storm's accuracy was increased to 75% and lasts four to five turns.
If a Binding Band is held by the user, the damage done at the end of each turn will increase from 1/16 of the target's maximum HP to 1/8.

Generation VI

Magma Storm's base power is now 100. Also, the end turn damage of Magma Storm is increased from 1/16 to 1/8 of the target's maximum HP. If the user is holding a Binding Band, the end turn damage of Magma Storm will increase to 1/6 of the target's maximum HP.

In the manga

In the Pokémon Adventures manga

Heatran opens its mouth and releases an extremely powerful stream of fire from its mouth at the opponent. If the opponent gets hit by the flames, the flames will surround the opponent, trapping it inside.